Personalized Reference Intervals Versus Indirectly Estimated Population‐Based Reference Intervals for Hematology Measurands

BACKGROUND: Interpretation of laboratory data is a comparative process that requires reliable reference intervals (RIs) to support clinical decision-making. Although population-based reference intervals (popRIs) are commonly used for this purpose, more accurate interpretation can be achieved using RIs derived from an individual's own data-that is, personalized reference intervals (prRIs). In this study, we estimated prRIs for common hematology parameters and compared them with popRIs indirectly derived from laboratory data. METHOD: popRIs were estimated for a total of 17 complete blood count (CBC) subparameters using patient laboratory data. prRIs for the same parameters were calculated using longitudinal data from 200 healthy individuals, based on a prediction interval model. Additionally, the reference interval index (RII) was calculated as the ratio of the range of prRIs to the range of popRIs for each measurand. RESULTS: prRIs calculated for CBC parameter differed from the corresponding popRIs. The median of RII varied from 0.41 for eosinophils to 2.97 for platelet distribution width (PDW). CONCLUSION: We concluded that the prRIs of the CBC parameters differ from their corresponding popRIs, and that prRIs should be used for a more accurate interpretation of patients' CBC results.